Terrorist group Islamic state executed their first Western hostage in September, 2014 with the gruesome beheading of James Foley. Since then the group has executed dozens of others includes their own deserters. Here is a look at some of the hostages whose executions have gained the most international attention.

Terrorist group Islamic state executed their first Western hostage in September, 2014 with the gruesome beheading of James Foley. Since then the group has executed dozens of others includes their own deserters. ... more

Photo: AP2014

Terrorist group Islamic state executed their first Western hostage... Photo-7510338.102970 - Times Union

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Kayla Mueller's parents reported to the media on Tuesday, February 10, 2015 that they have been notified of their daughter's death.

Earlier a statement that appeared on a militant website commonly used by the Islamic State group claimed that Mueller, an aid worker kidnapped in Turkey, was killed in a Jordanian airstrike on Friday, Feb. 6, 2015, on the outskirts of the northern Syrian city of Raqqa, the militant group's main stronghold. The IS statement could not be independently verified.

Kayla Mueller's parents reported to the media on Tuesday,... Photo-7510340.102970 - Times Union

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Jordanian pilot Lt. Muath al-Kaseasbeh was reportedly executed by being lit on fire by Islamic State on Tuesday, February 3, 2015.

Since childhood, Muath al-Kaseasbeh had dreamed of becoming a pilot, but in recent months refused to share his feelings about Jordan's bombing missions against Islamic State militants, his family says.

Jordan's participation in the U.S.-led military coalition against the Islamic State group is unpopular in the pilot's home village of Ay and the nearby provincial town of Karak, said his brother, Jawdat. "People here believe our boys shouldn't fight outside the country," he said. "They should fight only in defending the soil of the country."

Al-Kaseasbeh, 26, was one of eight siblings — four boys and four girls. After high school he attended flight college. In 2009, after graduation, he joined the military and began flying F-16s and other warplanes, earning the rank of lieutenant. "Since his childhood, he wanted to be a pilot," Jawdat, 30, said of his brother.

Al-Kaseasbeh got married last year to a woman from a nearby village, a university graduate, and the young couple moved to Karak. Jawdat said his brother is a devout Muslim and had joined his parents on a pilgrimage to Mecca, Saudi Arabia.

The pilot's F-16 went down over northern Syria in December, near the Islamic State group's de facto capital of Raqqa, and he ejected. Militants pulled him out of the Euphrates River.

He became the first foreign military pilot to fall into the extremists' hands since the international coalition began its air strikes.

Kenji Goto was not a thrill seeker, his friends and relatives say. He had been covering wars because he is committed to social justice and wants to tell the world about the suffering of people in conflict zones.

Goto was survived by wife Rinko and two young daughters, a newborn and a 2-year-old.

The 47-year-old Goto set up his own video news company, Independent Press, in 1996, mainly covering refugees, children and poverty in war-torn countries. He had contributed reports to major Japanese networks and has worked with U.N. organizations and nonprofit groups. He had also written books about children in conflict zones and lectured at Japanese schools.

In late October, just two weeks after his wife gave birth to their child, Goto left for Syria to try to rescue his assistant, 42-year-old Haruna Yukawa, who had been captured and beheaded by Islamic State militants.

Goto was also seized by the militants, with his Twitter feed ending Oct. 23.

Japanese video journalist Kenji Goto was executed in January 2015.... Photo-7510345.102970 - Times Union

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Taboola Gallery Frame Item-85307.102970 - Times Union

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Haruna Yukawa, right, a Japanese citizen and self-styled security contractor, was executed in January 2015.

Goto seems to have been a mentor to Yukawa, a weapons geek who wanted to set up a private security service despite having few language skills and scant experience. Goto rescued Yukawa from an anti-government militant group in Syria early last year, and since then the two had traveled together in Syria a few times before the younger man was taken hostage last summer.

Haruna Yukawa, right, a Japanese citizen and self-styled security... Photo-7510347.102970 - Times Union

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The Islamic State jihadist group executed American aid worker Peter Kassig on November 16, 2014.

Kassig first went to the Middle East with the Army, which he joined in 2006, according to his military records.

He ultimately served in the 75th Ranger Regiment, a special operations unit, and served in Iraq from April until July 2007 before being medically discharged as a private first class that September.

His desire to perform aid work in the region was kindled during a March 2012 spring break trip to Beirut while he was studying political science at Butler University. Kassig, a certified EMT, left school and returned two months later to Lebanon, where he worked as a medical assistant and humanitarian worker and treated people from all sides of the conflict in neighboring Syria.

French mountaineer Herve Gourdel was beheaded by Islamist militants in Algeria in September 2014.

An Algerian splinter group from al-Qaida has beheaded a French hostage over France's airstrikes on the Islamic State group.

The killing of Herve Gourdel, a mountaineer who was kidnapped while hiking in Algeria, was a "cowardly assassination," a visibly upset French President Francois Hollande said, but he vowed to continue the military operation.

"France will never cede to terrorism because it is our duty, and, more than that, because it is our honor," Hollande said at the U.N. General Assembly meeting in New York.

France had joined the U.S. in conducting airstrikes on the Islamic State group in Iraq. Two days later, the Islamic State group called on Muslims to attack foreign targets.

Gourdel, 55, of Nice, was seized Sunday night while hiking in the Djura Djura mountains.

A group calling itself Jund al-Khilafah, or "Soldiers of the Caliphate," split from al-Qaida and pledged allegiance to the Islamic State group two weeks ago. It seized Gourdel in response to the call to kill the "spiteful and filthy French."

Islamic State executed British aid worker David Haines before in... Photo-7510356.102970 - Times Union

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Steven Sotloff

, a freelance journalist for Time magazine and The Jerusalem Post, was beheaded in September, 2014.

The video horrified Americans and journalists around the world and touched a nerve in Israel, where news of Sotloff's connections to the country dominated newscasts and brought condolences from Israelis who knew the Miami-area native.

"Steve was part of a group of young Jewish Americans who are enamored with Israel and enamored with the Arab world," said Ehud Yaari, an Arab affairs commentator for Israeli Channel 2 who met Sotloff. "They were dying to know and enter all the dangerous places, and that's how he behaved."

Steven Sotloff , a freelance journalist for Time magazine and The... Photo-7510358.102970 - Times Union

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In a horrifying act of revenge for U.S. airstrikes in Iraq, Islamic State extremists posted a video of American journalist James Foley's execution on August 19, 2014 — the first in a series of beheadings of Westerners by ISIS.

Foley, 40, worked in a number of conflict zones in the Middle East, including Syria, Libya and Iraq. He and another journalist were working in the northern province of Idlib in Syria when they were kidnapped near the village of Taftanaz.

After Foley disappeared, while contributing video for Agence France-Presse and the media company GlobalPost, his parents became fierce advocates for him and all those kidnapped in war zones.

They held regular prayer vigils and worked with the U.S. and Syrian diplomatic corps to get whatever scraps of information they could.

Diane Foley, asked in January 2013 if her son had reservations about going to Syria, said softly: "Not enough."

He had seen the dangers to journalists up close. Upon his release from Libya and return to the United States, he recalled in an interview seeing a colleague, South African photographer Anton Hammerl, killed by forces loyal to Libyan leader Moammar Gadhafi. He tried to pull his friend's body out of harm's way but was turned back by heavy fire.

"I'll regret that day for the rest of my life. I'll regret what happened to Anton," Foley said. "I will constantly analyze that."

Foley grew up in New Hampshire and studied history at Marquette University. He later taught in Arizona, Massachusetts and Chicago before switching careers to become a journalist, which he viewed as a calling.

In a horrifying act of revenge for U.S. airstrikes in Iraq, Islamic State extremists posted a video of American journalist James Foley's execution on August 19, 2014 — the first in a series of beheadings of ... more

Photo: Uncredited, HONS

In a horrifying act of revenge for U.S. airstrikes in Iraq, Islamic... Photo-7510360.102970 - Times Union